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HomeMy WebLinkAboutHORSETOOTH-TIMBERLINE PROPERTY - MASTER PLAN - 78-88 - SUBMITTAL DOCUMENTS - ROUND 1 - TRAFFIC STUDY00 m g MI --;I M CD N M CD CO co O co CD z w w z C7 z w J CU z O_ H H O a CIO 11 U- U- cc F- MEHORAIADUM To: Charles Deane, W.W. Reynolds Companies City of Fort Collins Staff From: Matt Delich �T Date: September 28, 1988 Subject: Timberline—Horsetooth Property Traffic Study I am submitting the traffic study as a. draft due to late authorization to proceed with this work. The text is in final form while the graphics are "mock ups" that will be formalized in the next few days. The appendices will be in the final report, which will be submitted during the week of October 3, 1988. Thank you. 0 ? I )SITE ACCESS STUD*-( PROPERTY FORT COLLINS, COLORADO SEPTEMBER 1988 Prepared for: W. W. Reynolds Companies 1919 14th Street, Suite 802 P. O. Box 1666 Boulder, CO 80306 Prepared by: MATTHEW J. DELlCH, P.E. 3413 Banyan Avenue Loveland, Colorado 80538 Phone 303-669-2061 EXECUTIVE SUMMARY Timberline-Horsetooth Property is a proposed development located near the intersection of Horsetooth Road and Timberline Road. This traffic impact study involved the steps of trip generation, trip distribution, trip assignment, capacity analysis, traffic signal warrant analysis, signal progression analysis_., and accident analysis. This study assessed the impacts of the Timberline- Horsetooth Property on the short range (1992) and long range (2010) street system in the vicinity of the proposed development. As a result of this analysis., the following is concluded: - The development of the Timberline-Horsetooth Property is feasible from a traffic engineering standpoint. At full development as proposed, approximately 12,500 trip ends will be generated at this site daily. - The Horsetooth/Timberline intersection currently operates acceptably with signal control and the existing geometrics. - By 1992, given the first phase of development of the Timberline-Horsetooth Property; Phase 1 of Collindale Business Park; Phases 1, 2, and 3 of Fox Meadows; and an increase in background traffic, the signalized intersection of Horsetooth/Timberline will operate acceptably with the existing geometrics and left -turn signal phases. At this level of development, Timberline Road and Horsetooth Road can remain two lane streets with auxiliary lanes at the access to Parcel A. Left -turn exits at the Horsetooth/Access intersection will operate unacceptably during the afternoon peak hour. There is little that can be done to improve this operation. There will be left -turn storage conflicts between the Timberline/Horsetooth intersection and the Horsetooth/ Access intersection. - No new signals are warranted in the short range future. With full development of the Timberline-Horsetooth Property and other nearby properties, signals will likely be warranted at the Timberline/Big Horn and the Horsetooth/ Access intersections. - Signals at the Timberline/Caribou and Timberline/Big Horn intersections will not negatively impact the signal progression along Timberline Road. The signal at the Horsetooth/Access intersection will not negatively impact the signal progression along Horsetooth Road. This intersection will function as a minor signalized intersection. By 2010, the Horsetooth/Timberline intersection will operate acceptably in the peak hours with geometric improvements to both Horsetooth Road and Timberline Road. The necessary geometrics are shown in Figure 10. With signalization, the Horsetooth/Access and Timberline/Big Horn intersections will operate acceptably. The proposed right- in/right-out access to Timberline will operate acceptably. It must be placed at a distance from Hor•setooth Road based upon the design speed of Timberline Road. A right -turn deceleration lane should be designed at this access. The proposed right-in/right-out access from Horsetooth Road is projected to have little effect on traffic generated at this site. It will primarily serve as a convenience access to the southern portion of the site. Consideration should be given to eliminating this access in order to emphasize the main access to Parcel A. - With the recommended control and geome tr i cs, the accident rate should be at an acceptable level for typical urban conditions. I. INTRODUCTION This traffic impact study addresses the capacity, geometric, and control requirements at and near a proposed development known hereinafter as the Timberline-Horsetooth Property. It is located near the intersection of Timberline Road and Horsetooth Road in Fort Collins, Colorado. During the course of the analysis, numerous contacts were made with the developer MI. W. Reynolds Companies), the planning consultant (Citxscape), and the Fort Collins Traffic Engineering Department. This study generally conforms to the format set forth in the Traffic Impact Study Guideline.. The study involved the following steps: - Collect physical, traffic and development data. - Perform trip generation, trip distribution, and trip assignment. - Determine peak hour traffic volumes and daily traffic volumes. - Conduct capacity and operational level of service analyses on key intersections and roadway sections. - Analyze signal warrants and signal progression. - Analyze potential changes in accidents and safety considerations. II. EXISTING CONDITIONS The location of the Timberline-Horsetooth Property is shown in Figure 1. It is important that a thorough understanding of the existing conditions be presented. Land Use Land uses in the area are primarily vacant, agricultu- ral, industrial, or recreational. Vacant land exists to the south. This is the location of a proposed industrial park known as Collindale Business Park. An agricultural use exists to the northeast across Horsetooth/Timberline intersection. The Collindale Golf Course is to the west of the site across the Union Pacific Railroad tracks. North of the site is the facility of the Platte River Power Authority. To the east, across Timberline Road is farm property. This property is the location of a proposed residential/commercial development known as Fox Meadows. Land in the area is essentially flat. The center of Fort Collins lies to the north of the Timberline-Horsetooth Property. 1 f' O#j M aF Gt to Swre LOC.A-TIO*',) FIGuFE 0 • Roads The primary streets near the Timberline-Horsetooth Property are Horsetooth Road and Timberline Road. Timberline Road is east of the Timberline-Horsetooth Property. It is a north -south street designated as a major arterial on the Fort Collins Master Street Plan. In this area, it has a two lane rural cross section with auxiliary turn lanes at Horsetooth Road. The posted speed limit is 40 mph. Sight distance is generally not a problem along Timberline Road. The Horsetooth/Timberline intersection has signal control. The nearest other signal along Timberline Road is at Prospect to the north and Harmony to the south. Horsetooth Road borders this site on the north. It is an east -west street designated as an arterial on the Fort Collins Master Street Plan. East of Timberline Road, Horsetooth Road is built to a half urban street cross section. West of Timberline Road, it is built to the full urban arterial cross_. section. There are left -turn lanes at the Horsetooth/Timberline intersection. The posted speed on Horsetooth Road is 40 mph west of Timberline and 45 mph east of Timberline. Existing Traffic Daily traffic flow is shown in Figure 2. These are machine counted volumes conducted by the City of Fort Collins in 1984. Peak hour turning movements obtained in June, 1988 are shown in Figure 3. Raw traffic count data is provided in Appendix A. Existing Operation The Horsetooth/Timberline intersection, which was counted in June 1988, was evaluated regarding operational efficiency. It was evaluated using existing signal control with existing geometrics and the volumes shown in Figure 3. The peak hour operation is shown in Table 1. Calculation forms are provided in Appendix B. Appendix C describes level of service for signalized and unsignalized intersections from the 1985 Highway Capacity Manual. With the existing control, this intersection operates acceptably except that left -turns do not always clear. This can be remedied by introducing a left -turn phase on each approach. Even with the additional time needed for the left -turn phase, acceptable operation is achieved. E • 2) o I a(, L956 (I°)83� N 0 0 co w 1541 ( I-) a3) Zcc J w HORSETO OTH sM Ir s �o M � co N RECENT DAILY TRAFFIC COUNTS w J w m _ oar � L Ln J I 8 41,/143 2/1 ICl/8a } HORSETOOTH IZZ/ 67- —1, I 105/°fZ �\ N 0 � � N � O � N FIGURE 2 AM/PM 1988 PEAK HOUR TRAFFIC FIGURE 3 E • Table 1 Existing Peak Hour Operation Intersection AM Peak Hour PM Peak Hour Timberline/Horsetooth Existing Geometric_/Phasing A t0.22) A f0.32? Existing Geometr i c_/Heav i est A 40.37? A (0.42) LT protected Table 2 Trip Generation Daily A.M. Peak: P.M. Peak Lend Use Trip=. Trips Trips Trips Trips in out in out Phase 1 - Parcel A Retail - 155.5 KSF 7720 Full Development Parcel B Office/Ind.- 100.0 KSF ?70 Parcel C Commercial - 31.75 KSF 1580 Parcel U Commercial - 25.0 KSF 1240 Parcel E Office - 40.0 KSF 500 Parcel F Office/Ind. - 55.0 KSF 530 Total 12540 138 12? 82 403 412 125 116 28 17 82 84 22 1.j "5 6 70 ? 12 ti 5 71 10 14 64 458 14? 601 807 III. PROPOSED DEVELOPMENT Timberline-Horsetooth Property is a proposed retail/ industrial/office park development located southwest of the Horsetooth/Timberline intersection in Fort Collins. Figure 4 shows a schematic of the site plan of the Timberline- Horsetooth Property indicating location of the uses shown in Table 2, Trip Generation. The short range analysis (1992) included Parcel A - Neighborhood Service Center indicated in Table 2 as Phase 1. The plan for Phase 1 shot -is an access from Timberline Road on the east and two accesses from Horsetooth Road on the north. The proposed access near the railroad tracks and the access from Timberline Road to Parcel A are intended to be right-in/right out. The right-in/right- out near the railroad tracks also serves as an access to the southern portion of the site. This access would not have a significant function in the development of Parcel A. The long range analysis (2010) included full development of the Timberline-Horsetooth Property development along with other proposed/expected uses to the south and east of this site and an increase in background traffic in general accordance with the North Front Range Corridor Study. Trip Generation Trip generation is important in considering the impact of a development such as this upon the existing and proposed street system. A compilation of trip generation information was prepared by the Institute of Transportation Engineers in 1976, updated in 1983, and was used to project trips that would be generated by the proposed uses at this site. These rates were supplemented using Development and Application of Trip Generation Rates, FHWA, January 1985. Table 2 shows the expected trip generation on a daily and peak hour basis. For the office/light industrial use, a composite trip generation factor was developed assuming a 50/50 split of these two uses. The neighborhood service center and commercial uses used shopping center trip generation factors. Based upon analysis of the trip generation tables, the shopping center use would cover the grocery store and other retail uses intended for this site. No adjustments were made for transit or ridesharing. Therefore, the trip generation can be considered conservatively high. Trip Distribution Two directional distributions of the generated trips were determined for the Timberline-Horsetooth Property. Distributions from the intended uses used population as the attraction variable in the gravity model. Future year data were obtained from information supplied by the Fort Collins 3 0 0 Igo SITE KAO 0 E Planning Department. The trip distributions are shown in Figure S. Traffic Projections Traffic projections for the short range time period (1992) were obtained by factoring the existing traffic by 108 percent (27% per year) for Horsetooth Road and for Timberline Road to obtain the expected traffic in 1992. Also included in the traffic projections were developments to the east (Fox Meadows) and to the south (Col1indala Business Park), which were likely to be partially developed by 1992. This traffic is identified as background traffic which passes by the site on Timberline Road and Horsetooth Road. Figure 6 shows the expected 1992 daily traffic considering the site generated traffic and the background traffic. For 20+ year projections (year 2010), the usual source for projections is. the Traffic Flow Map as provided by the City. However, the last Traffic Flow Map provides projections for only the year 2000. The North Front Range Corridor Study is also used as a reference. Therefore, an estimation was made of traffic in this area by the year 2010 using the latest Traffic Flow Map, the North Front Range Corridor Study, and the knowledge of what has been occurring and what is expected to occur in this area. of Fort Collins. These daily projections are shown in Figure 7. These volumes assume that the system indicated on the Fort Collins Master Street Plan is in place. Trip Assignment Trip assignment is how the generated and distributed trips are expected to be loaded on the street system. The assigned trips are the resultant of the trip distribution process. Figure 8 shows the short range morning peak hour assignment and the afternoon peak hour assignment of Phase 1 of the Timberline-Horsetooth Property generated traffic plus background traffic. Figure 9 shows the long range peak hour assignment of full development of the Timberline-Horsetooth Property with background traffic, assuming implementation of the road network indicated on the Fort Collins Master Street Plan. Si gnat Warrants As a matter of policy, traffic signals are not installed at any location unless warrants are met according to the Manual on Uniform Traffic Control Devices. However, it is possible to determine whether traffic signal warrants are likely to be met based upon estimated ADT and peak hour 0 • 0 30� t s 30, agA �- He Inc- TooT M 6 St1oRT ZANaC--//,p,0iG 40Gt �iP D isTK1BUTio0 n O 0 N 93on No 2SE ToCT14 DAU-V TAFFIC 0 16 0 0 N' M Z�, o0o Z I' Q00 j�o25�TouT1{ S� Tt J 0 W 0 N LONG RANEE DAILY TAFFiC. FIr,ueE 7 U pg ?A p S/I 1615-3 -8/18� f>ACCeL A A41PM � N r N �- go/Z 3`j /57/142- 1-�4/1 $Z M M 10 3t4.,,,e-r ZA,,KC PcAK HoOP. 7RAFFIC more serooTrl Flauge 8 0 0 9 � O \O 2 SO��Uo I Z 4) �-- 8 gO�1440 � (� m M L 97(15/Z"s �% .�«_.....:.:,..gar.... Z2o/zoo .�r..�.eru9:pa�ar.,-e,.....,.,_.,.,.,=`.—_.ae: zes.=Yerms�er�..—+-+.:�� Y.w++w`=�, 14-15/9„--a s/� �' ._rt.r...�t-�s,...rww+n•u•sno+maa+maa-�-.e..., °1 �(� 4001-Z o9D J :�n. `l 1 r' NorseTroTN 10135- Co0 9 0 �• 4.70/Z8O--'► i6-& 016Z 9 O ONO N � 00 0 m s� 3 s/< A MIPM W 2 J 0� w to �l F- a a Im 70 /9 s' $►ts Hoeg v �- 00 LONG �ANt.E PEAK Xuf— 7RAPFIC. F%cur 0 i signal warrants shown in Appendix D. Using the daily traffic volumes, a signal is not warranted at the Horsetooth/Access intersection. Using the peak hour traffic shown in Figure 8, a signal is not warranted in the morning peak hour, but is warranted in the afternoon peak hour. It is recommended that a signal not be installed in the short range future. Operation will be discussed later in this report. Using the traffic volumes in Figures 7 and 9, a traffic signal is likely to be warranted at the Timberline/Big Horn and the Horsetooth/Access intersections. Big Horn Drive is in the Fox Meadows development on the east side of Timberline Road and in the Timberline-Horsetooth Property on the west side of Timberline Road. Signal Progression Signal progression was evaluated prior to intersection operational analysis in order to evaluate whether the potentially warranted signals at the Timberline/Big Horn Road and Horsetooth/Access intersections can fit into a signal progression pattern along Timberline Road and Horsetooth Road, respectively. Other signals along Timberline Road and Horsetooth Road were inserted based upon judgment and included signals which would yield a reasonable level of analysis. The technique used in the signal progression analysis was a computer program called Signal Progression Analysis (SPAN) prepared by the University of Florida Transportation Research Center. Its main functions include: - Interactive entry of arterial system data. - Display a time location diagram which provides graphical representation of the quality of arterial progression. - Printing of a time -space diagram to show the quality of progression. - Optimization of signal offsets for arterial pro- gression. The program inputs are: - Intersection location - Cycle length - Phasing - Offsets - Speed Any or all of these inputs can be changed iteratively in achieving the optimal progression. 5 0 • The signal progression on Timberline Road was analyzed based upon the following criteria: - Cycle length of 90-120 seconds. - Posted speed of 35-40 mph. - Mainline (Timberline) G/C Ratio Drake G/C = 0.40 Collector G/C = 0.60 Collector G/C = 1.00 (no signal) Horsetooth G/C = 0.40 Big Horn G/C = 1.00 (no signal), G/C = 0.75 (with signal) Caribou G/C = 1.00 (no signal), G/C = 0.60 (with signal) Harmony G/C = 0.40 - Green time on the cross street is greater than the pedestrian crossing time of the mainline at 4 feet per second. - Achieve the largest bandwidth possible along Timber- line Road. A number of cycle lengths and speeds were examined. Appendix E shows four progression analyses for Timberline Road. Page 1 shows a time -space diagram using a 90 second cycle and 40 mph with no signal at Big Horn Drive and Caribou Drive. Bandwidths of 31 seconds (34% efficiency) are achieved in each direction. Page 2 shores the same criteria with signals introduced at Big Horn Drive and Caribou Drive. The bandwidths are the same as those indicated on Page 1. Page 3 shows a time -space diagram using a 100 second cycle and 35 mph with no signals at Big Horn Drive and at Caribou Drive. Bandwidths of 37 seconds (37;. efficiency) are achieved in each direction. Page 4 shows the same criteria with signals introduced at Big Horn Drive and Caribou Drive. The bandwidths are the same as those indicated on Page 3. It is concluded that signals at Big Horn Drive and Caribou Drive will not negatively impact signal progression along Timberline Road. The signal progression on Horsetooth Road was analyzed based upon the following criteria: - Cycle length of 90-100 seconds (same as the selected cycle lengths on Timberline) - Posted speed of 35-40 mph. - Mainline (Horsetooth) G/C Ratio Parcel A Access. G/C = 0.70 Timberline G/C = 0.40 Arctic Fox G/C = 0.60 Caribou G/C = 0.60 Johnson Farm Collector G/C = 0.60 Additional Johnson Farm intersection G/C = 1.00 (no signal) County Road 9 G/C = 0.50 6 Green time on the cross street is greater than the pedestrian crossing time of the mainline at 4 feet per second. - Achieve the largest bandwidth possible along Horse - tooth Road. Pages 1-8 of Appendix F show time -space diagrams for Horsetooth Road. Pages 1, 3, 5, and 7 show the signal pro- gression without a signal at the Horsetooth/Access inter- section. Pages 2, 40 6, and 8 show the signal progression with a signal at the Horsetooth/Access intersection. The bandwidths are the same for each matching set of speed and cycle length criteria. It is concluded that a signal at the Horsetooth/Access intersection will not negatively impact signal progression along Horsetooth Road. The Horsetooth/Access intersection is approximately 600 feet from Timberline. This is sometimes called a minor signalized intersection. This concept was recommended in the "Access Control Demonstration Project," prepared for the Colorado Department of Highways, District 6. It has been a method of providing access to corner properties located at the intersections of major arterial streets. It has been implemented in the City of Lakewood. The Lakewood Traffic Engineering Department was contacted to gain some insight with regard to their experience with this concept. The following comments were made: - The access point proposed for signalization must have much lower traffic volumes when compared to the major street. A "rule of thumb" ratio of greentime is 1/3 versus 2/3. - The left -turn lane storage requirements on the major street at the arterial/arterial intersection take precedence over the location of a signal at the access. - The access signal should have as few phases as. possible. A two or three phase signal seems to work best. A full eight phase signal is unacceptable. - At the intersection of two arterials, it is acceptable to introduce signals at the accesses on two legs, but not on all four legs. The minor signalized intersection concept has been implemented in Lakewood on two adjacent legs at the Wadsworth/Jewell intersection. Wadsworth Boulevard is a six lane arterial which is also State Highway 121. Jewell Avenue is a four lane arterial. The Lakewood Traffic Engineering Department stated that these signals have been performing satisfactorily, serving the adjacent land uses and not negatively impacting either Wadsworth Boulevard or Jewell Avenue. Based upon the preceeding progression analyses, the operational and geometric analyses provided later in this 7 • report, and the acceptability of this concept in the State of Colorado, it is recommended that the minor signalized intersection concept be considered at this location. Final determination is subject to more refined "design level" studies. The above progression analyses are presented to shov., that the Horsetooth/Access and Timberline/Big Horn signals can fit into a progression pattern along the respective streets. Design progression analysis must be conducted on a regular basis reflecting change in land use, speed, and other variables. Operations Analysis Capacity analyses were performed on key intersections adjacent to the Timberline-Horsetooth Property. The short range analyses were performed on the Horsetooth/Timberline and Horsetooth/Access intersections due to the proposed phasing of this development. The long range analyses were performed on all the key intersections. Using the traffic volumes shown in Figure 8 and the existing geometrics, the intersections operate in the short range condition as indicated in Table 3. Calculation forms for these analyses are provided in Appendix G. The Horsetooth/Timberline intersection operates acceptably with traffic signals. It is recommended that, at a minimum, left - turn phases be provided for the heaviest movement north/south and east/vlest. If the changes in traffic cannot be detected by the available equipment, then fixed -time left -turn phases will be necessary. This will be less efficient, but the level of service will remain in acceptable categories. The left -turn lanes should be: eastbound - 150-200 feet; southbound - 100-130 feet; westbound - 70-90 feet; and northbound - 150-200 feet at this level of development. The stop sign controlled Horsetooth/Access intersection will operate unacceptably during the afternoon peak hour. Left -turn exits from this access will be in the level of service E category. It is common that this movement will fall into unacceptable operational levels prior to signals being warranted. There is little that can be done to remedy this. The delays to these left -turn movements will likely occur for only a portion of the afternoon peak hour and should be accepted. Provision of a left -turn lane on the Access viill confine delays to only those vehicles desiring to turn left. Left- and right -turn auxiliary lane• are required at the Horsetooth/Access intersection. The right -turn auxiliary lane should be 370 feet (including taper) given the 40 mph posted speed. The existing cross section on this portion of Horsetooth Road accommodates five lanes. The existing curb lane can possibly be used for this auxiliary 8 Table 3 Short Range Peak. Hour Operation Intersection AM Peak Hour FM Peak: Hour Timberline/Horsetooth Existing Geometries/Heaviest A (0.51) C: (0 • ) LT protected Hor _.etooth Acce_•_• EB LT A A WB LT A A S B LT C: E SB RT/T A A NB LT C E NB RT/T A A Timberline/Right-in/Right-out EB RT A A Table 4 Lang Range Peak Hour Operation Intersection AM Peak Hour PM Peak: Hour Timberl ine'Horsetooth 4 lane + LT & RT lanes on C (0.76) D (0.78) Horse tooth/6 lane + SBLT lanes + 2 NBLT lanes + MINT lanes on Timberline Horsetooth/Acre_._. A (0.49) B (0.57) Timberline/Big Horn A (0.42) B (0.58) Timberline/Right-in/Right-out EB RT A A Hor _•etooth/Right-i n/R.i ght-out NB RT A A right -turn lane since the short range projection does not indicate the need for two through lanes in each direction from a capacity point of view. The left -turn lane (westbound) into this access should be 370 feet (deceleration and taper) plus 120 feet (storage), totalling 490 feet. This is almost the full distance between Timberline and this access. This westbound auxiliary lane would conflict with the eastbound left -turn lane at the Horsetooth/Timberline signalized intersection. Using the desirable length for the eastbound left -turn lane (200 feet + taper), the longest westbound left -turn lane at the access would be 180 feet. Using the minimum length for the eastbound left -turn lane (150 + taper), the longest westbound left -turn lane at the access would be 230 feet. A right-in/right-out access to Parcel A is proposed from Timberline Road. Due to deceleration lane requirements (370 feet using the posted speed), this access should be approximately 455 feet south of the south curbline of Horsetooth Road. If this is physically not possible, the design will need to be coordinated with the Fort Collins Traffic Engineer. Not having the right-in/right-out access to Timberline Road would require almost 20 percent of the trips generated by Parcel A to utilize the main access at Horsetooth Road. This will further increase the westbound left -turn requirements (discussed earlier) at the Horsetooth/Access intersection. Under the short range future condition, Timberline Road and Horsetooth Road require a two lane cross section with the auxiliary lanes mentioned above. The above analyses and recommendations also include development of Phases 1, 2, and 3 of the Fox Meadows development and Phase 1 of the Collindale Business Park. Other development which may occur in the area is reflected in the 2 percent per year increase of the background (existing) traffic. Using the traffic volumes shown in Figure 9, the key intersections operate in the long range future as indicated in Table 4. Calculation forms for these analyses are provided in Appendix H. It is expected that by this future date (2010), the Timberline-Horsetooth Property, as well as a number of other parcels, will be at full development. In order to attain acceptable operation during both peak hours at the Horsetooth/Timberline intersection, it is recommended that each approach be provided with the geometrics shown in Figure 10. Even with these geometric improvement=_, the operation of this intersection falls into marginal level of service D in the afternoon peak hour. Since this will likely occur for only a few cycles of the afternoon peak hour, it should be accepted. The Timberline/Big Horn signalized intersection will operate acceptably. The geometrics at this intersection are also shown in Figure 10. 9 s d r m .9 d2g-a'-34o� i-TArea N o R S E'TOOTH i 's 8 i IZ d I a e N ,y �-° BIG t4cu FY 8 Ifr LONG RAkIr,e Ge oM U TRICS I-Ir, up,(' 10 0 • The signalized Horsetooth/Access intersection will operate acceptably. The recommended geometrics are shown in Figure 10. The desirable left -turn lane requirements for the Horsetooth/Access and Horsetooth/Timberline intersections total 650 feet plus taper. This is in excess of the available distance between these two intersections. The only way to meet the geometric requirements is to provide a double eastbound left -turn lane at the Horsetooth/Timberline intersection. If the double eastbound left -turn lanes are selected as an option, then the operation of the Horsetooth/ Timberline intersection will improve over that shown in Table 4. As in the short range analysis, the proposed right- in/right-out from Timberline Road will require a deceleration lane based upon the posted speed of Timberline Road. At the current 40 mph, a deceleration lane of 370 feet including taper is required. Based upon design considerations on other Fort Collins development projects, a design speed of less than 40 mph should not be used. As stated in the short range analysis, this access should be approximately 455 feet south of the south curbline of Horsetooth Road. A right-in/right-out access has been proposed from Horsetooth Road just east of the railroad tracks. This access will serve primarily as a site circulation access to Parcels B, C, D, E, and F and a service access to Parcel A. The number of vehicles utilizing this access will be fairly low (estimate <10% of the generated trips). This access will have little effect on the operation of any of the other key intersections analyzed. Consideration should be given to eliminating this access and providing the main access to Parcel A with an adequate deceleration lane. This would emphasize the main access to Parcel A, the retail area. If this right-in/right-out access is approved, it can be controlled by the at -grade railroad crossing gates that exist on Horsetooth Road. Traffic projections indicate the need for a right -turn auxiliary lane. If the City requires the auxiliary lane, it should also be controlled by the gates. This would necessitate constructing a new gate base on the south side of Horsetooth with longer gate arms. Accident Analysis The recommended control devices and geometrics should minimize vehicular conflicts and maximize vehicle separation. Therefore, the accident rate should be at its minimum for a typical urban condition. 10 I V . CONCLUSIONS This study assessed the impacts of the Timberline- Horsetooth Property on the short range (1992) and long range (2010) street system in the vicinity of the proposed development. As a result of this analysis, the following is concluded: - The development of the Timberline-Horsetooth Property is feasible from a traffic engineering standpoint. At full development as proposed, approximately 12,500 trip ends will be generated at this site daily. - The Horsetooth/Timberline intersection currently operates acceptably with signal control and the existing geometrics. - By 1992, given the first phase of development of the Timberline-Horsetooth Property; Phase 1 of Collinda.le Business Park; Phases 1, 2, and S of Fox Meadows; and an increase in background traffic, the signalized intersection of Horsetooth/Timberline will operate acceptably with the existing geometrics and left -turn signal phases. At this level of development, Timberline Road and Horsetooth Road can remain two lane streets with auxiliary lanes at the access to Parcel A. Left -turn exits at the Horsetooth/Access intersection will operate unacceptably during the afternoon peak hour. There is little that can be done to improve this. operation. There will be left -turn storage conflicts between the Timberline/Horsetooth intersection and the Horsetooth/ Access intersection. - No new signals are warranted in the short range future. With full development of the Timberline-Horsetooth Property and other nearby properties, signals will likely be warranted at the Timberline/Big Horn and the Horsetooth/ Access intersections. - Signals at the Timberline/Caribou and Timberline/Big Horn intersections will not negatively impact the signal progression along Timberline Road. The signal at the Horsetooth/Access intersection will not negatively impact the signal progression along Horsetooth Road. This. intersection will function as a minor signalized intersection. - By 2010, the Horsetooth/Timberline intersection will operate acceptably in the peak hours with geometric improvements to both Horsetooth Road and Timberline Road. The necessary geometrics are shown in Figure 10. With signalization, the Horsetooth/Access and Timberline/Big Horn intersections will operate acceptably. The proposed right- in/right-out access_• to Timberline will operate acceptably. It must be placed at a distance from Horsetooth Road based it • • upon the design speed of Timberline Road. A right -turn deceleration lane should be designed at this access. The proposed right-in/right-out access from Horsetooth Road is projected to have little effect on traffic generated at this site. It will primarily serve as a convenience access to the southern portion of the site. Consideration should be given to eliminating this access in order to emphasize the main access to Parcel A. - With the recommended control and geometrics, the accident rate should be at an acceptable level for typical urban conditions. 12 1 N Fr ti A c_...